Document wr9gRB5B1V1OY7yjKkjbd247B

656 CHAPTER 46 1959 Guide *Application Engineering Standard for Year-Round Resi dential Air Conditioning (Air Conditioning and Refrigeration Institute, 610-56). 4 Summer Air Conditioning (National Warm Air Heating and Air Conditioning Association, Manual No. 11, 1955). 'Continuous Air Circulation (National Warm Air Heating and Air Conditioning Association, Manual No. 6, 1955). M. E. Childs, R. W, Roose, H. T. Gilkey, and S. Konzo: Comparative Performances of Two Warm Air Perimeter Sys tems and Three Convection Systems (University of Illinois, Engineering Experiment Station Bulletin 403, 1942). TD. R. Bahnfleth, C. F. Chen, and H. T. Gilkey: Cooling a small residence "g a perimeter-loop duct system (ASHVE Transactions, VoL 60, 1954, p. 271). 'H. E. Straub and S. F. Gilman: Room air distribution research for year-round air conditioning. Part II--Supply out lets at three floor locations (ASHVE Transactions, Vol. 60, 1954, p. 249). A. P. Krats, M. K. Fahnestock, and 8. Konzo: Investiga tion of Summer Cooling tn the Warm Air Heating Research Residence (University of Illinois, Engineering Experiment Sta tion Bulletin 290, 1930). " R. A. Gonsales: How power usage varies for summer air conditioning of identical residences (.Refrigerating Engineering, January 1957, p. 35). aT. N. Wiilcox: Annual utility cost operating residential filing system (Fuel Oil News, June 1954). "S. F. Gilman, L. A. Hall, and E. P. Palmatier: The oper ating cost of residential cooling equipment (ASHVE Transac tions, Vol. 60,1954, p. 525). "S. 8. Visher: Relative cooling requirements for American homes (The Scientific Monthly, November 1945, p. 211). "E N. Kemler and 8. Oglesby: Heat Pump Applications (McGraw-Hill Book Co., New York, 1950, 1st ed., p. 246). "Summer Weather Data (The Marley Co., Kansas City, 1939, Chapter VI). CHAPTER 47 SCHOOL SYSTEMS General Consrderofions, Criteria for Design, Design Considerofions. Preliminary Design, Mechanical Plant Design, Types of Ventilating Systems, Types of Heating and Cooling Systems, Automatic Control, Operation, Maintenance he purpose of this chapter is to outline the factors af requirements. Many schools include multipurpose rooms Tfecting the selection of heating, ventilating, and air- serving as auditoriums, gymnasiums, and community centers. conditioning systems for schools. The components of these The normal periods of operation are five days per week systems are the same as used for other types of buildings. for nine months per year, with complete shutdown during Their combination in school systems, in some cases, will be week-ends and vacation periods. Few schools operate during the same as for other buildings, but may differ considerably the summer months and therefore do not require complete in others in order to provide optimum conditions for effec air conditioning, except in southern climates. Systems for tive school work and to comply with local regulations. administration areas, gymnasiums, auditoriums, and multi purpose rooms, suitable for community activities, will often GENERAL CONSIDERATIONS be operated at times when the systems for classrooms and other general educational areas may not be in operation. The proper criteria for heating, ventilating, and in many Automatic control of temperature and system equipment instances air conditioning, of school buildings, particularly is a necessity if comfortable conditions are to be obtained. classrooms, are often not recognized fully. Proper application of controls may return the cost of in Many designers and school administrators approach the vestment by savings in labor and fuel within a year or two. problem as one of heating, whereas analysis may show Frequently, insufficient consideration is given to provi that cooling, rather than heating, is required during periods sions for access and maintenance with the idea that the of occupancy throughout most of the year. Ventilation mechanical system is a fixed part of the structure and should systems are frequently designed to supply air at 72 F for last as long as the structure, without attention. ventilation and, when feasible, at 55 F to 60 F to provide School boards are often criticized by their constituents for the cooling required during occupancy. spending large sums of money for so-called luxury items, with With regard to ventilation, code requirements vary from the result that economy in construction and design becomes acceptance of natural ventilation, such as obtained by a paramount factor. This often tends to limit size of the me opening of windows, to a requirement of mechanical supply chanical equipment selected below that required to maintain of a specified quantity of air, which sometimes is as high a proper indoor atmospheric environment. However, many as 30 cfm of outdoor air per occupant. The variations in schools in areas having warm spring and fall climates are now quantity of outdoor air specified are due to the hasis adopted being designed to include air conditioning, at least in spaces whether it is the quantity needed to replace oxygen for of densest occupancy and greatest use. breathing or that required for the dilution of odors. A discussion of air requirements will be found in Chapter 6. CRITERIA FOR DESIGN When piinning for introduction of ventilation air into Comfort, cleanliness, reduction of odors, maintenance of rooms, careful consideration should be given to air dis alertness, compliance with codes, installation cost, ease and tribution and circulation within the occupied space, as well cost of upkeep, cost of operation, and adaptability to con as the natural convection and temperature effects. trol in relation to periods of use as related to outdoor con Elementary schools of recent design are generally single- ditions are the chief, criteria by which a design for main story buildings, often placed at considerable distance from tenance of indoor environment for learning may be judged. each other. They are often provided with windows 7 ft Comfort, which may be defined as freedom from strain in or more in height extending the full length of one or more accommodating to the environment, is a necessity. Uniform classroom walls. These large glass areas constitute one of ity of air movement and temperature within the space is re the greatest problems in maintaining an optimum indoor quired to provide a comfortable environment. Fundamentals atmospheric environment. in this respect are discussed in Chapter 6, Physiological Secondary or high schools are more often two- and three- Principles, and Chapter 20, Air Distribution. Intermittent story structures but present problems only slightly less currents of air or air movement at varying velocities may severe than grade schools. Separation of school buddings result in discomfort. Similarly, variations in temperature results in increased cost of the mechanical systems. may contribute more to discomfort than uniform main A further characteristic of school buildings is a wide tenance of slightly higher or lower temperatures. variation in use and occupancy. Classrooms (the largest Odors, while they may not be deleterious to health, are single group of occupancies), lecture rooms, assembly rooms, disagreeable and distracting, even to the point of being nau auditoriums, and other similar areas have uniformly dense seating. Odors should not be perceptible in schoolrooms. occupancies. Gymnasiums, cafeterias, laboratories, shops, Local codes may establish requirements for construction, and similar functional spaces have lighter occupancies and glass areas, ventilation rates, etc., which exceed values used also have different and varying ventilation temperature in normal design practice. 657